1. Field of the Invention
The present invention relates in general to heat spreaders for semiconductor packages and, more particularly, to a structural improvement in such a heat spreader for commonly using the heat spreader for varieties of surface mounting packages, such as MQFP, TOFP, PLCC, TSOP and SOJ, regardless of pad sizes of the semiconductor packages.
2. Description of the Prior Art
In the early stage of semiconductor packaging development, an integrated circuit (IC) was packaged by a metal can or packaged between ceramic lid and base. Both packaging materials, or the metal can and the ceramic lid and base, provide good thermal performance for the IC packages. However, the above packaging materials have a problem that they are considerably expensive and need to be packaged through a troublesome packaging technique, which technique wastes much time. For example, in a ceramic package, it is noted that the cost caused by use of two ceramic substrates forms a considerable part of the total cost of the ceramic package.
Watched with keen interest among the developed cheaper packages are plastic packages. The plastic packages remarkably reduce the cost for production of packages, however, the plastic packages have a problem that they are lacking of good thermal performance, which performance can be effected by the typical metal or ceramic packages. As the data processing speed of the IC packages becomes faster and as the density of the IC packages is increased, the IC packages need to be improved in their thermal performance. That is, it is necessary to improve the thermal emission ability of the IC packages. In an effort to effectively emit the heat from the IC chip of the IC package to the outside without affecting the operational reliability of the package due to mechanical designing of the package and due to associated assembly process, a metal heat spreader is preferably installed in the IC package.
However, the typical metal heat spreader has a problem that it needs to be changed with another spreader in accordance with pad size of the package. This problem will become worse particularly when the pad has either a slot or a through hole.